Philip Seymour Hoffman died from a fatal mix of heroin, cocaine and prescription pills, coroners have ruled.

The tragic Capote star, 46, passed away from a suspected drug overdose at his Manhattan apartment on February 2, but an initial autopsy proved inconclusive.

Officials at the city's medical examiner's office conducted further toxicology and tissue tests, and the results have since revealed he had anti-anxiety medication benzodiazepines and stimulants amphetamines in his system, in addition to the illegal substances.

The mixing of heroin and cocaine is known as speedballing - the same combination that killed comedian John Belushi and actor River Phoenix, reports TMZ.com.

Hoffman's official cause of death has been listed as acute mixed drug intoxication. The Hollywood star was found dead with a needle still stuck in his arm.